The purposes of this study will be 1) to determine the HPV types associated with pre-cancerous cervical lesions, cervical intraepithelial neoplasia III (CIN III), also called carcinoma-in- situ; 2) to determine the presence and possible involvement of other infectious agents, such as HSV-II, CMV, and chlamydia; and 3) to ascertain the effect of other exposures, such as smoking, contraceptive method (oral contraceptives), and nutrition. This population-based case-control study will identify women 45 years old or less in Group Health Cooperative of King County, one of the largest HMOs in the United States, with newly diagnosed CIN III from October, 1986 through March, 1991. We plan to identify the cases through the Pathology Department of Group Health and the Cancer Surveillance System, a population-based cancer registry. We estimate we will be able to interview approximately 350 cases of carcinoma-in-situ (CIN III). The control group will consist of approximately 350 women of the same ages and county of residence who are identified through the enrollment files of Group Health. All previous cytologic specimens of cases and controls will be collected and evaluated for the presence of HPV by means of in-situ hybridization and cytologic features. The histologic specimens of all cases will also be tested for specific HPV types, HSV-II, and CMV. Data from an in-person interview and blood will also be collected.